Merge branch '131-windows-uninstall-leaves-registry-entries' into 'master'

Fix deletion of RegisteredApplication RegValues

The Registry Values in all RegisteredApplication Keys get properly deleted now.

Also `HKCU\Software\Forschungszentrum Juelich GmbH` is deleted if it only has one entry (which then is `PeTrack`). If it has multiple entries, i.e. some other software was installed under the same registry key, only `HKCU\Software\Forschungszentrum Juelich GmbH\PeTrack` gets deleted.

Closes #131

See merge request !81